System Health Management E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Aerospace Series (PEP)
• Sprache: Englisch

Seitenzahl: 1506

Veröffentlichungsjahr: 2011

Beschreibung

System Health Management: with Aerospace Applications provides the first complete reference text for System Health Management (SHM), the set of technologies and processes used to improve system dependability. Edited by a team of engineers and consultants with SHM design, development, and research experience from NASA, industry, and academia, each heading up sections in their own areas of expertise and co-coordinating contributions from leading experts, the book collates together in one text the state-of-the-art in SHM research, technology, and applications. It has been written primarily as a reference text for practitioners, for those in related disciplines, and for graduate students in aerospace or systems engineering.

There are many technologies involved in SHM and no single person can be an expert in all aspects of the discipline.System Health Management: with Aerospace Applications provides an introduction to the major technologies, issues, and references in these disparate but related SHM areas. Since SHM has evolved most rapidly in aerospace, the various applications described in this book are taken primarily from the aerospace industry. However, the theories, techniques, and technologies discussed are applicable to many engineering disciplines and application areas.

Readers will find sections on the basic theories and concepts of SHM, how it is applied in the system life cycle (architecture, design, verification and validation, etc.), the most important methods used (reliability, quality assurance, diagnostics, prognostics, etc.), and how SHM is applied in operations (commercial aircraft, launch operations, logistics, etc.), to subsystems (electrical power, structures, flight controls, etc.) and to system applications (robotic spacecraft, tactical missiles, rotorcraft, etc.).

Leseprobe

Table of Contents

Title Page

Copyright

Dedication

About the Editors

List of Contributors

Foreword

Preface

Part One: The Socio-technical Context of System Health Management

Chapter 1: The Theory of System Health Management

Overview

1.1 Introduction

1.2 Functions, Off-Nominal States, and Causation

1.3 Complexity and Knowledge Limitations

1.4 SHM Mitigation Strategies

1.5 Operational Fault Management Functions

1.6 Mechanisms

1.7 Summary of Principles

1.8 SHM Implementation

1.9 Some Implications

1.10 Conclusion

Bibliography

Chapter 2: Multimodal Communication

Overview

2.1 Multimodal Communication in SHM

2.2 Communication Channels

2.3 Learning from Disaster

2.4 Current Communication in the Aerospace Industry

2.5 The Problem of Sense-making in SHM Communication

2.6 The Costs of Faulty Communication

2.7 Implications

2.8 Conclusion

Acknowledgments

Bibliography

Chapter 3: Highly Reliable Organizations

Overview

3.1 The Study of HROs and Design for Dependability

3.2 Lessons from the Field: HRO Patterns of Behavior

3.3 Dependable Design, Organizational Behavior, and Connections to the HRO Project

3.4 Conclusion

Bibliography

Chapter 4: Knowledge Management

Overview

4.1 Systems as Embedded Knowledge

4.2 KM and Information Technology

4.3 Reliability and Sustainability of Organizational Systems

4.4 Case Study of Building a Learning Organization: Goddard Space Flight Center

4.5 Conclusion

Bibliography

Chapter 5: The Business Case for SHM

Overview

5.1 Business Case Processes and Tools

5.2 Metrics to Support the Decision Process

5.3 Factors to Consider in Developing an Enterprise Model

5.4 Evaluation of Alternatives

5.5 Modifications in Selected Baseline Model

5.6 Modeling Risk and Uncertainty

5.7 Model Verification and Validation

5.8 Evaluation Results

5.9 Conclusion

Bibliography

Part Two: SHM and the System Lifecycle

Chapter 6: Health Management Systems Engineering and Integration

Overview

6.1 Introduction

6.2 Systems Thinking

6.3 Knowledge Management

6.4 Systems Engineering

6.5 Systems Engineering Lifecycle Stages

6.6 Systems Engineering, Dependability, and Health Management

6.7 SHM Lifecycle Stages

6.8 SHM Analysis Models and Tools

6.9 Conclusion

Acknowledgments

Bibliography

Chapter 7: Architecture

Overview

7.1 Introduction

7.2 SHM System Architecture Components

7.3 Examples of Power and Data Considerations

7.4 SHM System Architecture Characteristics

7.5 SHM System Architecture Advanced Concepts

7.6 Conclusion

Bibliography

Chapter 8: System Design and Analysis Methods

Overview

8.1 Introduction

8.2 Lifecycle Considerations

8.3 Design Methods and Practices for Effective SHM

8.4 Conclusion

Acknowledgments

Bibliography

Chapter 9: Assessing and Maturing Technology Readiness Levels

Overview

9.1 Introduction

9.2 Motivating Maturity Assessment

9.3 Review of Technology Readiness Levels

9.4 Special Needs of SHM

9.5 Mitigation Approaches

9.6 TRLs for SHM

9.7 A Sample Maturation Effort

9.8 Conclusion

Bibliography

Chapter 10: Verification and Validation

Overview

10.1 Introduction

10.2 Existing Software V&V

10.3 Feasibility and Sufficiency of Existing Software V&V Practices for SHM

10.4 Opportunities for Emerging V&V Techniques Suited to SHM

10.5 V&V Considerations for SHM Sensors and Avionics

10.6 V&V Planning for a Specific SHM Application

10.7 A Systems Engineering Perspective on V&V of SHM

10.8 Conclusion

Acknowledgments

Bibliography

Chapter 11: Certifying Vehicle Health Monitoring Systems

Overview

11.1 Introduction

11.2 Durability for VHM Systems

11.3 Mechanical Design for Structural Health Monitoring Systems

11.4 Reliability and Longevity of VHM Systems

11.5 Software and Hardware Certification

11.6 Airworthiness Certification

11.7 Health and Usage Monitoring System Certification Example

11.8 Conclusion

Acknowledgments

Bibliography

Part Three: Analytical Methods

Chapter 12: Physics of Failure

Overview

12.1 Introduction

12.2 Physics of Failure of Metals

12.3 Physics of Failure of CMCs

12.4 Conclusion

Bibliography

Chapter 13: Failure Assessment

Overview

13.1 Introduction

13.2 FMEA

13.3 SFMEA

13.4 FTA

13.5 SFTA

13.6 BDSA

13.7 Safety Analysis

13.8 Software Reliability Engineering

13.9 Tools and Automation

13.10 Future Directions

13.11 Conclusion

Acknowledgments

Bibliography

Chapter 14: Reliability

Overview

14.1 Time-to-Failure Model Concepts and Two Useful Distributions

14.2 Introduction to System Reliability

14.3 Analysis of Censored Life Data

14.4 Accelerated Life Testing

14.5 Analysis of Degradation Data

14.6 Analysis of Recurrence Data

14.7 Software for Statistical Analysis of Reliability Data

Acknowledgments

Bibliography

Chapter 15: Probabilistic Risk Assessment

Overview

15.1 Introduction

15.2 The Space Shuttle PRA

15.3 Assessing Cumulative Risks to Assist Project Risk Management

15.4 Quantification of Software Reliability

15.5 Description of the Techniques Used in the Space Shuttle PRA

15.6 Conclusion

Bibliography

Chapter 16: Diagnosis

Overview

16.1 Introduction

16.2 General Diagnosis Problem

16.3 Failure Effect Propagation and Impact

16.4 Testability Analysis

16.5 Diagnosis Techniques

16.6 Automation Considerations for Diagnostic Systems

16.7 Conclusion

Acknowledgments

Bibliography

Chapter 17: Prognostics

Overview

17.1 Background

17.2 Prognostic Algorithm Approaches

17.3 Prognosis RUL Probability Density Function

17.4 Adaptive Prognosis

17.5 Performance Metrics

17.6 Distributed Prognosis System Architecture

17.7 Conclusion

Bibliography

Part Four: Operations

Chapter 18: Quality Assurance

Overview

18.1 NASA QA Policy Requirements

18.2 Quality System Criteria

18.3 Quality Clauses

18.4 Workmanship Standards

18.5 Government Contract Quality Assurance

18.6 Government Mandatory Inspection Points

18.7 Quality System Audit

18.8 Conclusion

Bibliography

Chapter 19: Maintainability: Theory and Practice

Overview

19.1 Definitions of Reliability and Maintainability

19.2 Reliability and Maintainability Engineering

19.3 The Practice of Maintainability

19.4 Improving R&M Measures

19.5 Conclusion

Bibliography

Chapter 20: Human Factors

Overview

20.1 Background

20.2 Fault Management on Next-Generation Spacecraft

20.3 Integrated Fault Management Automation Today

20.4 Human–Automation Teaming for Real-Time FM

20.5 Operations Concepts for Crew–Automation Teaming

20.6 Empirical Testing and Evaluation

20.7 Future Steps

20.8 Conclusion

Bibliography

Chapter 21: Launch Operations

Overview

21.1 Introduction to Launch Site Operations

21.2 Human-Centered Health Management

21.3 SHM

21.4 LS Abort and Emergency Egress

21.5 Future Trends Post Space Shuttle

21.6 Conclusion

Bibliography

Chapter 22: Fault Management Techniques in Human Spaceflight Operations

Overview

22.1 The Flight Operations Team

22.2 System Architecture Implications

22.3 Operations Products, Processes and Techniques

22.4 Lessons Learned from Space Shuttle and ISS Experience

22.5 Conclusion

Bibliography

Chapter 23: Military Logistics

Overview

23.1 Focused Logistics

23.2 USMC AL

23.3 Benefits and Impact of SHM on Military Operations and Logistics

23.4 Demonstrating the Value of SHM in Military Operations and Logistics

23.5 Conclusion

Bibliography

Part Five: Subsystem Health Management

Chapter 24: Aircraft Propulsion Health Management

Overview

24.1 Introduction

24.2 Basic Principles

24.3 Engine-Hosted Health Management

24.4 Operating Conditions

24.5 Computing Host

24.6 Software

24.7 On-Board Models

24.8 Component Life Usage Estimation

24.9 Design of an Engine Health Management System

24.10 Supporting a Layered Approach

24.11 Conclusion

Bibliography

Chapter 25: Intelligent Sensors for Health Management

Overview

25.1 Introduction

25.2 Sensor Technology Approaches

25.3 Sensor System Development

25.4 Supporting Technologies: High-Temperature Applications Example

25.5 Test Instrumentation and Non-destructive Evaluation (NDE)

25.6 Transition of Sensor Systems to Flight

25.7 Supporting a Layered Approach

25.8 Conclusion

Acknowledgments

Bibliography

Chapter 26: Structural Health Monitoring

Overview

26.1 Introduction

26.2 Proposed Framework

26.3 Supporting a Layered Approach

26.4 Conclusion

Acknowledgments

Bibliography

Chapter 27: Electrical Power Health Management

Overview

27.1 Introduction

27.2 Summary of Major EPS Components and their Failure Modes

27.3 Review of Current Power System HM

27.4 Future Power SHM

27.5 Supporting a Layered Approach

27.6 Conclusion

Bibliography

Chapter 28: Avionics Health Management*

Overview

28.1 Avionics Description

28.2 Electrical, Electronic and Electromechanical (EEE) Parts Qualification

28.3 Environments

28.4 Failure Sources

28.5 Current Avionics Health Management Techniques

28.6 Avionics Health Management Requirements

28.7 Supporting a Layered Approach

28.8 Conclusion

Bibliography

Chapter 29: Failure-Tolerant Architectures for Health Management

Overview

29.1 Introduction

29.2 System Failure Response Stages

29.3 System-Level Approaches to Reliability

29.4 Failure-Tolerant Software Architectures for Space Missions

29.5 Failure-Tolerant Software Architectures for Commercial Aviation Systems

29.6 Observations and Trends

29.7 Supporting a Layered Approach

29.8 Conclusion

Acknowledgments

Bibliography

Chapter 30: Flight Control Health Management

Overview

30.1 A FC Perspective on System Health Management

30.2 Elements of the FC System

30.3 FC Sensor and Actuator HM

30.4 FC/Flight Dynamics HM

30.5 FC HM Benefits

30.6 Supporting a Layered Approach

30.7 Conclusion

Bibliography

Chapter 31: Life Support Health Management

Overview

31.1 Introduction

31.2 Modeling

31.3 System Architecture

31.4 Future NASA Life Support Applications

31.5 Supporting a Layered Approach

31.6 Conclusion

Bibliography

Chapter 32: Software

Overview

32.1 Sampling of Accidents Attributed to Software Failures

32.2 Current Practice

32.3 Challenges

32.4 Supporting a Layered Approach

32.5 Conclusion

Bibliography

Part Six: System Applications

Chapter 33: Launch Vehicle Health Management

Overview

33.1 Introduction

33.2 LVSHM Functionality and Scope

33.3 LV Terminology and Operations

33.4 LV Reliability Lessons Learned

33.5 LV Segment Requirements and Architecture

33.6 LVSHM Analysis and Design

33.7 LV LVSHM System Descriptions

33.8 LVSHM Future System Requirements

33.9 Conclusion

Bibliography

Chapter 34: Robotic Spacecraft Health Management

Overview

34.1 Introduction

34.2 Spacecraft Health and Integrity Concerns for Deep-Space Missions

34.3 Spacecraft SHM Implementation Approaches

34.4 Standard FP Implementation

34.5 Robotic Spacecraft SHM Allocations

34.6 Spacecraft SHM Ground Rules and Requirements

34.7 SFP and SIFP Architectures

34.8 Conclusion

Bibliography

Chapter 35: Tactical Missile Health Management

Overview

35.1 Introduction

35.2 Stockpile Surveillance Findings

35.3 Probabilistic Prognostics Modeling

35.4 Conclusion

Bibliography

Chapter 36: Strategic Missile Health Management

Overview

36.1 Introduction

36.2 Fundamentals of Solid Rocket Motors

36.3 Motor Components

36.4 Challenges for Strategic Rocket Health Management

36.5 State of the Art for Solid Rocket System Health Management (SHM)

36.6 Current Challenges Facing SRM SHM

36.7 Conclusion

Bibliography

Chapter 37: Rotorcraft Health Management

Overview

37.1 Introduction

37.2 Rotorcraft System Health Management Standard Practices

37.3 New Practices

37.4 Lessons Learned

37.5 Future Challenges

37.6 Conclusion

Bibliography

Chapter 38: Commercial Aviation Health Management

Overview

38.1 Commercial Aviation Challenge

38.2 Layered Approach to SHM

38.3 Evolution of Commercial Aviation SHM

38.4 Commercial State of the Art

38.5 The Next Generation: Intelligent Vehicles/Sense and Respond

38.6 Conclusion

Bibliography

Glossary

Acronyms

Index

This edition first published 2011

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Library of Congress Cataloguing-in-Publication Data

System health management: with aerospace applications / edited by Stephen B Johnson … [et al.].

p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-74133-7 (hardback)

1. Aeronautics—Systems engineering—Quality control. 2. Astronautics—Systems engineering—Quality control. I. Johnson, Stephen B., 1959-

TL501.S97 2011

629.1–dc22

2011005628

A catalogue record for this book is available from the British Library.

Print ISBN: 978-0-470-74133-7

ePDF ISBN: 978-1-119-99404-6

Obook ISBN: 978-1-119-99405-3

ePub ISBN: 978-1-119-99873-0

Mobi ISBN: 978-1-119-99874-7

This book is dedicated to Joan Pallix, a pioneer in our field. Joan's ingenuity brought many of us together to develop early demonstrations of system health management technologies for the Space Shuttle Thermal Protection System, and her trailblazing approach provided a key foundation of the System Health Management process that we describe herein. Her dedication, originality, and technical expertise earned the respect of the System Health Management community.

About the Editors

Stephen B. Johnson has been active in the field of system health management since the mid-1980s. His experience includes the development of fault protection algorithms for deep-space probes, research into SHM processes within systems engineering, the development of SHM theory, the psychological, communicative, and social aspects of system failure, and the application of directed graph methods for assessment of testability, failure effect propagation timing, and diagnostic systems. He is the author of The Secret of Apollo: Systems Management in American and European Space Programs (2002) and The United States Air Force and the Culture of Innovation 1945–1965 (2002), the general editor of Space Exploration and Humanity: A Historical Encyclopedia (2010), and has written many articles on SHM and space history. He has a BA in Physics from Whitman College and PhD in the History of Science and Technology from the University of Minnesota. He currently is an associate research professor at the University of Colorado at Colorado Springs, and a health management systems engineer at NASA Marshall Space Flight Center.

Thomas J. Gormley has been involved in the aerospace industry for 24 years and brings a systems engineering and implementation perspective to this SHM textbook. He was the Integrated Vehicle Health Management Project leader for Rockwell Space Systems during the early 1990s and was the developer of the Propulsion Checkout and Control System that was successfully demonstrated on the next generation reusable launch system testbed. Mr. Gormley transferred to Lockheed-Martin Telecommunication Systems where he focused his efforts on fault protection systems for commercial telecommunications. In 2000 he formed Gormley & Associates and has been a consultant for NASA on several SHM projects. He is presently supporting NASA's Constellation Program Information Systems Office and is applying his systems engineering and health management expertise to NASA's Space Exploration Program. Mr. Gormley has published several technical papers on SHM and is a member of the American Institute of Aeronautics and Astronautics.

Seth S. Kessler is the president and CEO of the Metis Design Corporation, a small consulting firm that has specialized in structural health monitoring technologies for a decade. He has experience from managing more than three-dozen government-funded BAA, SBIR, and STTR contracts. His research interests have included distributed sensor network architectures, analytical modeling of guided waves, diagnostic algorithms for composite materials, and carbon nanotube (CNT) based multifunctional structures. In 1998 he received his SB in aerospace engineering at the Massachusetts Institute of Technology (MIT) studying the effects of a cryogenic environment on composite materials. In 1999, he received his SM from that same department, creating and experimentally validating a design tool to analyze composite structures subjected to extreme inertial loading. Dr. Kessler completed his PhD from MIT in 2002, researching structural health monitoring piezoelectric-based techniques for damage detection in composite structures. He also was a post-doc in that department, modeling durability effects in composite laminates as part of the DARPA-funded, Boeing-led Accelerated Insertion of Materials Program. Dr. Kessler was a Draper Fellow working on the DARPA seedling WASP Program, and at the Lockheed Martin Skunk Works was an advanced concepts engineer on the X33/VentureStar Program. In 1998, he received the Admiral Luis De Florez Award for Ingenuity and Creativity in Design, in 2001 was awarded the American Society for Composites PhD Research Scholarship, and was awarded Best Paper by ASC in 2002 and the PHM Society in 2009. Dr. Kessler has more than three-dozen technical publications and holds 10 patents in his areas of expertise.

Charles D. Mott brings expertise in the social and economic aspects of large-scale technological projects. He has experience in business process improvement, systems analysis and design, financial system design and implementation, and organizational management. He has worked at Bank One, Patriot Management Corporation, Don Breazeale and Associates, Dow Chemical, and NASA. He has a bachelor's degree in management information systems from Michigan Technological University and a masters in space studies from the University of North Dakota. He is a member of the Prognostics and Health Management Society.

Ann Patterson-Hine, PE, has worked at NASA Ames Research Center since 1988. She is the branch chief for Discovery and Systems Health in the Intelligent Systems Division. She has been the project leader for advanced technology demonstrations under the Next Generation Launch Technology Program and many of the program's predecessors including the Reusable Launch Vehicle and Space Launch Initiative Programs. She participated on the Shuttle Independent Assessment Team and Wire Integrity Pilot Study at Ames. She was Principal Investigator for NASA's Exploration Technology Development Program's Integrated Systems Health Management project. Her research has focused on the use of engineering models for model-based reasoning in advanced monitoring and diagnostic systems. She received a BS degree in mechanical engineering from The University of Alabama and a doctorate in mechanical engineering from The University of Texas at Austin, and is a member of the American Institute of Aeronautics and Astronautics and a senior member of the IEEE.

Karl M. Reichard is the a research associate at the Pennsylvania State University Applied Research Laboratory and assistant professor of acoustics. He is the head of the Applied Research Laboratory's Embedded Hardware/Software Systems and Applications Department and teaches and advises graduate students in The Pennsylvania State University Graduate Program in Acoustics and the Department of Electrical Engineering. He has over 25 years of experience in the design and implementation of signal processing, control, and embedded diagnostics/prognostics systems. He has developed unattended remote sensing, active control, and health monitoring systems for land- and sea-based platforms. He earned BS, MS, and PhD degrees in electrical engineering from Virginia Tech.

Philip A. Scandura, Jr. has over 25 years of experience in the system definition and implementation of real-time embedded systems, for use in safety-critical and mission-critical applications. Mr. Scandura joined Honeywell in 1984 where he is currently employed as a staff scientist in its Advanced Technology Organization. During his tenure at Honeywell, he has specified, designed, and tested avionics systems for use in commercial, regional, business, and commuter aircraft, as well as human-rated space vehicles. He served as system architect, contributing to the development of several integrated modular avionics (IMA) and integrated vehicle health management (IVHM) systems, including those used on the Boeing 777 aircraft family. Mr. Scandura served for eight years as a certified FAA Designated Engineering Representative (DER), specializing in the certification of critical systems and equipment for aircraft. He is the author of Chapter 22, “Vehicle Health Management Systems,” in The Avionics Handbook, Second Edition, edited by Cary R. Spitzer (CRC Press, 2006), and has written many papers on vehicle health management concepts. Mr. Scandura holds a BS degree in electrical engineering from the University of Missouri–Rolla and a MBA in technical management from the University of Phoenix.

List of Contributors

Gordon B. Aaseng, NASA Ames Research Center, USA

George Y. Baaklini, NASA Glenn Research Center, USA

Edmund C. Baroth, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Gary Bird, Microsoft Corporation, USA

Gautam Biswas, Vanderbilt University, USA

David E. Brinza, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Thomas Brotherton, Brotherton & Associates, USA

Barbara L. Brown, NASA Ames Research Center, USA

Edward N. Brown, The Boeing Company, USA

Robert M. Button, NASA Glenn Research Center, USA

Carl S. Byington, Impact Technologies, USA

Fu-Kuo Chang, Stanford University, USA

Savio Chau, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Amy Chicatelli, Qinetiq North America at NASA Glenn Research Center, USA

Michael Christensen, Honeywell International, USA

Alan Crocker, NASA Johnson Space Center, USA

Eddie C. Crow, Pennsylvania State University, Applied Research Laboratory, USA

Ryan W. Deal, NASA Marshall Space Flight Center and Miltec, a Ducommen Company, USA

Paula J. Dempsey, NASA Glenn Research Center, USA

Luis A. Escobar, Louisiana State University, USA

Martin S. Feather, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Robert A. Ferrell, NASA Kennedy Space Center, USA

Kai Goebel, NASA Ames Research Center, USA

Grant A. Gordon, Honeywell International, USA

Thomas J. Gormley, Gormley & Associates, USA

Ron Hodge, NASA Marshall Space Flight Center, USA

Todd Hong, NASA Johnson Space Center, USA

Brian K. Hughitt, NASA Headquarters, USA

Gary W. Hunter, NASA Glenn Research Center, USA

Kumar V. Jata, Air Force Research Laboratory, USA

Stephen B. Johnson, NASA Marshall Space Flight Center and University of Colorado at Colorado Springs, USA

Gregory J. Kacprzynski, Impact Technologies, USA

Kirby Keller, Boeing Research & Technology, USA

Anthony R. Kelley, NASA Marshall Space Flight Center, USA

Seth S. Kessler, Metis Design Corporation, USA

Yujun Kim, Stanford University, USA

David Kortenkamp, TRACLabs Inc., USA

Abdul J. Kudiya, United States Army Aviation and Missile Research, Development and Engineering Center, USA

Daniel Lutz, Honeywell International, USA

Robyn Lutz, NASA Jet Propulsion Laboratory, California Institute of Technology and Iowa State University, USA

Ryan M. Mackey, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Eric-Jan Manders, Vanderbilt University, USA

Johannes F.C. Markmiller, McKinsey & Company, Inc., Germany

Lawrence Z. Markosian, Stinger Ghaffarian Technologies at NASA Ames Research Center, USA

Stephen A. Marotta, United States Army Aviation and Missile Research, Development and Engineering Center, USA

Robert S. McCann, NASA Ames Research Center, USA

William Q. Meeker, Iowa State University, USA

Paula S. Morgan, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Charles D. Mott, Complete Data Management, USA

Priya Narasimhan, Carnegie Mellon University, USA

Sriram Narashimhan, University of California at NASA Ames Research Center, USA

Patricia E. Nicoli, NASA Kennedy Space Center, USA

Allen Nikora, NASA Jet Propulsion Laboratory, California Institute of Technology, USA

Lawrence G. Oberle, NASA Glenn Research Center, USA

Brian O'Hagan, NASA Johnson Space Center, USA

Gary O'Neill, Georgia Tech Research Institute, USA

Triplicane A. Parthasarathy, UES, Inc., USA

Clint Patrick, US Army Integrated Air and Missile Defense, USA

Ann Patterson-Hine, NASA Ames Research Center, USA

Krishna Pattipati, University of Connecticut, USA

Jose M. Perotti, NASA Kennedy Space Center, USA

James Poblete, Boeing Research & Technology, USA

Karl M. Reichard, Pennsylvania State University, Applied Research Laboratory, USA

Michael J. Roemer, Impact Technologies, USA

Edward W. Rogers, NASA Goddard Space Flight Center, USA

Gregory A. Ruderman, Air Force Research Laboratory, Edwards Air Force Base, USA

Beverly A. Sauer, BAS Consultants Inc., and NASA Goddard Space Flight Center, USA

Philip A. Scandura, Jr., Honeywell International, USA

Daniel P. Siewiorek, Carnegie Mellon University, USA

Lilly Spirkovska, NASA Ames Research Center, USA

Irem Y. Tumer, School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, USA

George Vachtsevanos, Impact Technologies, USA

Kosta Varnavas, NASA Marshall Space Flight Center, USA

William E. Vesely, NASA Headquarters, USA

Al Volponi, Pratt & Whitney, USA

Robert D. Waterman, NASA Kennedy Space Center, USA

Susan J. Waterman, NASA Kennedy Space Center, USA

Michael D. Watson, NASA Marshall Space Flight Center, USA

Andrew Wiedlea, Los Alamos National Laboratory, USA

Timothy J. Wilmering, Boeing Research & Technology, USA

Bruce Wood, Pratt & Whitney, USA

Jinkyu Yang, California Institute of Technology, USA

James J. Zakrajsek, NASA Glenn Research Center, USA

Alan J. Zide, NASA Kennedy Space Center, USA

Douglas J. Zimpfer, Charles Stark Draper Laboratory, USA

Foreword

In November of 2005, the editors of this volume and I organized a forum entitled Integrated System Health Engineering and Management (ISHEM) in Napa, California. The purpose of the forum was to recognize the relationship between traditional safety and reliability engineering methods and more recent approaches in detecting, diagnosing, and predicting failures of complex engineered systems. The particular title for the forum was chosen in order to highlight the tight coupling between engineering, operational, and management practices in this emerging field of study. We intended the forum to highlight the state of the art in system health management (SHM) at the time, with the forum papers providing the basis for the first reference textbook for the field. To that end, we invited 40 experts to present their perspectives on the state of the art in their respective fields of study. Five years later, we bring you this volume with expanded and updated versions of the forum papers as this book's chapters, and with additional topics that were not discussed in the original forum. We intend this volume to serve as a comprehensive reference for the state of the art in SHM as of 2010.

The field of SHM is based on some fundamental observations: all electromechanical components wear out as a function of time, use, and environmental conditions, and complex systems contain inherent design flaws that often reveal themselves only in operation. Over time, component aging may result in performance degradation, subsystem faults, or system failures. When designing safety-critical and mission-critical systems, engineers aim to prevent system failures or at least to minimize their impact. These systems have stringent reliability requirements. These reliability requirements are typically met using a combination of reliability engineering and risk management methods:

Fail-safe or fail-operational component/subsystem designs“Designing out” identified failure modesDesign margins (power, propulsion, supplies, etc.)Fault accommodationRedundant components and subsystemsRedundancy management techniques enabling fault tolerance for flight-critical functionsFault detection, isolation and recovery, FDIRFault protection.

A key intuition in SHM is that even though failures may not be avoidable, they are frequently predictable given the right instrumentation and appropriate physical models. Over the last few decades, the systems engineering community started investigating the fundamental principles of system failures in an attempt to understand how electromechanical components age and to predict when they might fail. With the emphasis shifting from population statistics (e.g., bathtub curves or Weibull statistics) to remaining useful life of individual components, a new discipline started to emerge. Several terms are used to refer to (variations of) SHM, including integrated systems health management (ISHM), integrated vehicle health management (IVHM), prognostics and health management (PHM), condition-based maintenance (CBM), enterprise health management, and health and usage monitoring systems (HUMS). Despite the recent emphasis on the field of SHM as a new discipline, health management for subsystems such as aircraft engines has been part of the engineering practice for well over 30 years.

As a systems engineering discipline, SHM addresses the design, development, operation, and lifecycle management of components, subsystems, vehicles, and other operational systems with the purpose of maintaining nominal system behavior and function and assuring mission safety and effectiveness under off-nominal conditions. While SHM concepts apply equally well to consumer products such as automobiles or computers, the discipline has its roots in aerospace applications that involve operations in hazardous or extreme environments. Examples include spacecraft operating in unfamiliar environments under extreme temperature variations, aircraft that are subject to frequent pressurization cycles and aerodynamic loads, and rocket motors that are very costly to test under off-nominal conditions.

For space exploration, SHM enables:

Autonomous (and automated) launch abort and crew escape capabilityEfficient testing and checkout of ground and flight systemsMonitoring and data analysis of ground and flight system operationsEnhanced situational awareness and control for ground personnel and crewVehicle autonomy (self-sufficiency) in responding to off-nominal conditions during long-duration and distant space missionsIn-space (autonomous) maintenance and repairEfficient ground processing of reusable systems.

For aircraft, SHM enables:

Efficient fault detection, isolation and recoveryPrediction of impending failures or functional degradationIncreased reliability and availability of mission systemsEnhanced vehicle situational awareness for crewsCondition-based and just-in-time maintenance practicesEfficient ground processing and increased asset availability.

It is important to note that SHM is not a substitute for traditional safety and reliability engineering methods. In contrast, SHM embraces and expands traditional engineering approaches to safety- and mission-critical systems design. Even though real-time systems monitoring and health management tasks constitute the majority of applications, the scope of SHM is not limited to real-time operations. Instead, SHM spans the entire systems lifecycle from design to verification, and from operations to logistics.

SHM methods have been deployed for flight-critical operations for decades, and there have been remarkable achievements in developing and maturing new SHM technologies over the last 10 years, However, there are relatively few commercial success stories in the deployment of advanced SHM technologies for maintenance and logistics operations. Even the most outstanding SHM technologies have no chance of deployment in a flight mission or aerospace vehicle if they do not address mission or program needs or reduce programmatic or technical risks. Earlier, I commented on the interplay between engineering and management as a core tenet of SHM. Accordingly, a successful SHM technologist needs to understand the relevant figures of merit for the target mission or program and determine what role the SHM technologies play in meeting those metrics. For aerospace systems, lifecycle cost, safety, reliability, and productivity are the most pertinent figures of merit that SHM systems might be able to address.

Lifecycle cost includes system acquisition costs as well as recurring operational costs. It is not uncommon to have service lifetimes of over 30 years for aerospace systems such as commercial or military aircraft or reusable spacecraft such as the Space Shuttle. With such long service lifetimes, maintenance, repair, and overhaul (MRO) costs dominate the total lifecycle cost for these platforms. Modern fighter aircraft are among the worst offenders in terms of service costs, with each flight-hour requiring nearly 30 person-hours of maintenance to inspect, overhaul, or replace mission-critical, life-limited components.

The Joint Strike Fighter (JSF, or F-35) Program has taken a revolutionary step to ease the conflict between cost and reliability: the F-35 is a single-engine fighter jet that is allowed to operate on aircraft carriers (the US Navy traditionally prefers multi-engine aircraft as an additional safety margin for flights over long stretches of ocean). Furthermore, the JSF Program has an ambitious goal of eliminating scheduled engine inspections entirely. The key to this bold move is prognostics, or the ability to determine remaining useful life of critical life-limited components in real time. Based on these prognostic technologies, the JSF Program aims to develop a comprehensive autonomic logistics infrastructure that will reduce system lifecycle costs while maintaining reliability margins.

Safety involves the safety of flight crews, passengers, ground support personnel, and the public. For crewed spacecraft and military aircraft, crew escape systems are commonly considered as a final risk mitigation strategy when mission-critical failures occur and there is no redundancy or safety margin available. In most cases, fault protection and accommodation methods serve as primary safety measures. For instance, modern aircraft such as the F-22 and F-35 incorporate failure accommodation methods that allow the aircraft to “limp back to base” following an in-flight failure or battle damage. Failure accommodation is typically achieved through sufficient safety margins and functional redundancy. Another principle is failure recovery, where an aircraft or spacecraft reconfigures its flight controls (autonomously or through crew intervention) in order to mitigate the impact of an in-flight failure and continue the mission. Finally, fault protection can halt system operation (safing) until the problem can be studied and remedied.

Reliability is directly related to maintenance costs and indirectly related to system safety. However, there are instances where safety and reliability are not necessarily related. Examples include nuclear power plants and weapon systems. Such systems are designed with the utmost concern for safety (of operators as well as the public). Reliability, important as it may be, is often a secondary concern decoupled from safety measures. On the other side of the spectrum, reliability is a top priority for robotic spacecraft destined for Solar System exploration while safety may not be a major concern—especially for those spacecraft that do not contain hazardous fuel or materials.

As a figure of merit, productivity includes asset availability (e.g., sortie rates or flights per day) and performance (e.g., ground turnaround time for a space or air vehicle). For science missions, productivity may be measured in terms of science return (e.g., experiments completed or measurement processed) or accomplishment of other mission goals. Asset availability is one of the most important figures of merit used to justify deployment of SHM technologies, since it is directly related to revenue for commercial assets or acquisition costs for military and space assets. Condition-based maintenance practices may help reduce asset downtime by minimizing “surprise” maintenance events, and reduced downtime may allow for smaller fleets to accomplish similar missions, thereby reducing acquisition costs.

Even though there are significant advances in health management technologies in fields such as structural health monitoring, aircraft avionics testing, non-destructive evaluation, prognostics, and physics of failure for mechanical components, deployment of new SHM technologies for aerospace operations remains as challenging now as it was a decade ago. Going forward, one of the most significant obstacles for new SHM technologies will continue to be limited deployment experience. This is especially the case with space systems applications where there is very little operational data from which statistically significant information could be derived. Coupled with the exceptional reliability of space-qualified systems, it is conceivable that the majority of the known failure modes may never be observed in actual space flight. In many cases, high-fidelity hardware-in-the-loop simulations are the only way to replicate certain failure modes and to observe their “signatures” so that effective failure detection and fault isolation techniques may be developed.

Given the advanced state of medicine today, it is difficult to recall that we did not understand the causation of heart disease, various cancers, or even more mundane ailments such as stomach ulcers only a few decades ago. As of 2010, the field of SHM is approximately as advanced as the field of medicine was in the 1970s. Today, we can detect the failure of subsystems with accuracy, but we may or may not be able to identify the root cause. X-ray and ultrasound-based inspection techniques are quite accurate or comprehensive. We return aerospace subsystems to service after intermittent failures that cannot be replicated on the test bench (euphemistically referred to as “no fault found” or “cannot duplicate” events in the aerospace vernacular). Yet, there are strong signs that investments in SHM over the last few decades are making a difference. We now have intriguing clues as to what might be causing intermittent failures of avionics units during flight. In the near future, we will have detailed physics-based models that might prevent us from experiencing catastrophic launch system failures like the Space Shuttle Challenger disaster. Pervasive structural sensing will help alleviate the need to increase safety margins (and weight) for composite aircraft out of fear, resulting in substantial fuel savings. Techniques developed to monitor rotorcraft drivetrains are already being applied to giant wind turbines, helping reduce the lifecycle cost of these investments in renewable energy. Insights into the chemistry and physics of battery aging are paving the way for batteries with better energy density and longer useful life—and thus helping fuel the electric vehicle revolution.

SHM has come a long way over the last couple of decades. This book documents recent significant advances in the basic theory and concepts of SHM, which have significant implications for the cost-effective implementation of SHM in the system lifecycle. I look forward to further maturation of current SHM technologies and the full integration of SHM principles into day-to-day operations of complex aerospace systems.

Serdar Uckun, MD, PhD

President, The Prognostics and Health Management Society, Palo Alto, CA, USA

October 2010

Preface

This book is predicated on the idea that SHM has been evolving into its own discipline over the course of the last 20 years, and has reached “critical mass.” The intent of this book is to provide a basic resource for those who work in, or interact with, one or more aspects of the many facets of SHM. Those experts will be familiar with their own sub-discipline, but not with the specifics of all of the related SHM fields that interact with it. Each chapter, written by an expert in the chapter subject, is intended to provide a basic overview for those with some familiarity with the field, but are not experts beyond one or two of the sub-disciplines. This is the typical situation for almost all “SHM engineers” and also for managers and researchers of SHM-related tasks and technologies. Whether we have hit the mark, the reader can judge for him- or herself.

There are many people I must thank, starting first with the editors and authors of this book. They have been an outstanding and disciplined group, leading to a quality product that was nearly on time. Those who have edited multi-author works realize that this is a minor miracle! Serdar Uckun, Ann Patterson-Hine, and Mike Watson set the stage for this book by supporting the ISHEM Forum that was the direct progenitor of this book.

Over the years, many people have contributed to the ideas of SHM as a discipline, leading to the contents of Chapter 1, which provides the framework for this book. In the 1980s while on the Magellan project, Whittak Huang and Ed Craig at Martin Marietta, and John Slonski and Chris Jones, taught me the basics of fault protection for deep-space missions. This implanted the idea that SHM is ultimately a set of system capabilities, not a technology. My Vehicle Health Management R&D team at Martin in the early 1990s, namely, Don Uhrich, Ron Grisell, Maxine Obleski, Ron Puening, and Glen Campbell, were instrumental in forming the first SHM methodology based on the systems engineering process. George Gilley of The Aerospace Corporation, and the Dependability Working Group, including Walt Heimerdinger and Dan Siewiorek from Carnegie Mellon, introduced me to the ideas of dependability theory. Don Uhrich, along with Larry Cooper from the University of Cincinnati, were instrumental in the development and publication in 1995 of the idea of SHM as a control loop. Mike Watson brought me to NASA in 2005, and provided the institutional base at Marshall Space Flight Center to develop the full-blown theory of SHM. John C. Day of Inspace Systems has been the single most influential person with whom I have worked to develop the mature theory described in this book, and Bob Rasmussen at JPL spurred the idea of SHM preserving functionality and has helped hone the theory. Finally, Mike Santi at MSFC, the Constellation Fault Management Terminology team, and my Functional Fault Analysis team from Ames Research Center (most particularly Eric Barszcz, Peter Robinson, and Jeremy Johnson), and Glenn Research Center (Bill Maul), and Lorraine Fesq's Fault Management Handbook team have all sharpened many of the ideas presented in Chapter 1.

Stephen B. Johnson

November 2010